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Hydraulic retarder has been widely applied on military vehicles and heavy commercial vehicles because of it could provide great brake torque and has lasting working time [1]. In order to reduce driver's frequent actions in braking process and prevent hydraulic retarder system from overheating, it is need to apply constant braking torque control, this control target has a strict requirement to hydraulic control system design. Many parameters often require repeated test to determine, which increases the R&D cost and extends the research cycle. This paper tries to find a time-efficient research method of hydraulic retarder control system through studying on a heavy military vehicle hydraulic retarder system. Hydraulic retarder model is set up through test data. The hydraulic control system is built based on AMESim. Controller model is set up based on PID control. The whole vehicle brake model is built based on MATLAB/Simulink.

Hydraulic retarder braking torque is needed to be controlled. Retarder braking torque refers to oil volume in retarder chamber, thus the key of braking torque control is oil charging & discharging control. The hydraulic oil charging & discharging system should have fast accurate response and provide enough flow rate. To achieve the requirement, the system is often complicated, many parameters need repeated test to determine, which increases the R&D cost and extends the research cycle. This paper tries to find a time-efficient research method on hydraulic retarder oil charging & discharging control system. The complete system is divided into some parts and every part is analyzed respectively based on mechanical theory and hydraulic theory. To build the precise model of all parts, the AMESim software is used.

Speed ratio and clamping force are two of the metal-belt CVT control targets. Conventional control strategies can not correspond to the driver's intention or provide various driving environment. A fuzzy logic ratio control algorithm and a fuzzy logic clamping force control algorithm for a metal-belt CVT are proposed. Nevertheless, high-quality fuzzy control rule base and factors of FLC are difficult to gain because repeated tests and experts' experience are needed. Therefore, genetic algorithm (GA) is introduced to optimize the fuzzy control algorithms. Using the optimized fuzzy control algorithms, Metal-belt CVT control simulations were implemented. The results show that a faster response and better robustness can be gained when compared with those of the PID control.

This paper shows a model based design method for PHEV hydraulic module. Firstly, system scheme is designed due to system function requirements and is verified preliminarily by function level modeling & simulation. Secondly, detailed models of hydraulic parts (hydraulic valves, actuators, etc…) are set up. Some part structure parameters are designed according to detailed model simulation. Thirdly, detailed hydraulic model is set up by parts model integration, the system design is further verified by completed model simulation. After prototype production, simulation result is compared with prototype test result and two results have good correlation. So this model based design method for PHEV hydraulic module is practical and has good effect on development period & cost reduction.